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-rw-r--r--lib/comp/zstd.c67
1 files changed, 61 insertions, 6 deletions
diff --git a/lib/comp/zstd.c b/lib/comp/zstd.c
index 4cbef38..2868cbf 100644
--- a/lib/comp/zstd.c
+++ b/lib/comp/zstd.c
@@ -3,6 +3,7 @@
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
+#include <ctype.h>
#include <zstd.h>
@@ -13,19 +14,36 @@
typedef struct {
compressor_t base;
ZSTD_CCtx *zctx;
+ int level;
} zstd_compressor_t;
+typedef struct {
+ uint32_t level;
+} zstd_options_t;
+
static int zstd_write_options(compressor_t *base, int fd)
{
- (void)base; (void)fd;
- return 0;
+ zstd_compressor_t *zstd = (zstd_compressor_t *)base;
+ zstd_options_t opt;
+ (void)fd;
+
+ if (zstd->level == ZSTD_DEFAULT_COMPRESSION_LEVEL)
+ return 0;
+
+ opt.level = htole32(zstd->level);
+ return generic_write_options(fd, &opt, sizeof(opt));
}
static int zstd_read_options(compressor_t *base, int fd)
{
- (void)base; (void)fd;
- fputs("zstd extra options are not yet implemented\n", stderr);
- return -1;
+ zstd_options_t opt;
+ (void)base;
+
+ if (generic_read_options(fd, &opt, sizeof(opt)))
+ return -1;
+
+ opt.level = le32toh(opt.level);
+ return 0;
}
static ssize_t zstd_comp_block(compressor_t *base, const uint8_t *in,
@@ -35,7 +53,7 @@ static ssize_t zstd_comp_block(compressor_t *base, const uint8_t *in,
size_t ret;
ret = ZSTD_compressCCtx(zstd->zctx, out, outsize, in, size,
- ZSTD_DEFAULT_COMPRESSION_LEVEL);
+ zstd->level);
if (ZSTD_isError(ret)) {
fputs("internal error in ZSTD compressor\n", stderr);
@@ -74,6 +92,7 @@ compressor_t *create_zstd_compressor(bool compress, size_t block_size,
{
zstd_compressor_t *zstd = calloc(1, sizeof(*zstd));
compressor_t *base = (compressor_t *)zstd;
+ size_t i;
(void)block_size;
if (zstd == NULL) {
@@ -81,6 +100,27 @@ compressor_t *create_zstd_compressor(bool compress, size_t block_size,
return NULL;
}
+ zstd->level = ZSTD_DEFAULT_COMPRESSION_LEVEL;
+
+ if (options != NULL) {
+ if (strncmp(options, "level=", 6) == 0) {
+ options += 6;
+
+ for (i = 0; isdigit(options[i]); ++i)
+ ;
+
+ if (i == 0 || options[i] != '\0' || i > 6)
+ goto fail_level;
+
+ zstd->level = atoi(options);
+
+ if (zstd->level < 1 || zstd->level > ZSTD_maxCLevel())
+ goto fail_level;
+ } else {
+ goto fail_opt;
+ }
+ }
+
zstd->zctx = ZSTD_createCCtx();
if (zstd->zctx == NULL) {
fputs("error creating zstd compression context\n", stderr);
@@ -93,8 +133,23 @@ compressor_t *create_zstd_compressor(bool compress, size_t block_size,
base->write_options = zstd_write_options;
base->read_options = zstd_read_options;
return base;
+fail_level:
+ fprintf(stderr, "zstd compression level must be a number in the range "
+ "1...%d\n", ZSTD_maxCLevel());
+ free(zstd);
+ return NULL;
+fail_opt:
+ fputs("Unsupported extra options for zstd compressor\n", stderr);
+ free(zstd);
+ return NULL;
}
void compressor_zstd_print_help(void)
{
+ printf("Available options for zstd compressor:\n"
+ "\n"
+ " level=<value> Set compression level. Defaults to %d.\n"
+ " Maximum is %d.\n"
+ "\n",
+ ZSTD_DEFAULT_COMPRESSION_LEVEL, ZSTD_maxCLevel());
}